It is proposed (a) to further study the ion movement and charge balance which result in depolarization of the Escherichia coli cell membrane by colicin E1; (b) to further study the proton movement which results in membrane energization; (c) to study changes in the cell envelope caused by colicin E1 or cessation of DNA synthesis; (d) to characterize colicin preparations which are fully active. BIBLIOGRAPHIC REFERENCES: The Effect of Colicin E1 on Proton Extrusion and the H ion/O Ratio in Escherichia coli, J.M. Gould, W.A. Cramer, and G. VanThienen, Biochem. Biophys. Res. Comm. 72, 1519-1525, 1976. Evidence for an increase in microviscosity of plasma membranes from soybean hypocotyls induced by the plant hormone, indole-3-acetic acid. S.L. Helgerson, W.A. Cramer, and D.J. Morre, Plant Physiology, 58, 548-551, 1976.